Morphological and compositional study of quartz and cassiterite of the Mocambo Granite, South Pará Tin Province, Amazonian Craton
Abstract Quartz and cassiterite crystals of granite, greisens, and quartz veins from Mocambo Granite, Carajás Province, were studied by scanning electron microscopy — cathodoluminescence and electron microprobe. Five types of quartz were identified: Qz1, magmatic and Qz2, Qz3, Qz4, and Qz5 hydrother...
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Sociedade Brasileira de Geologia
2020-11-01
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| Series: | Brazilian Journal of Geology |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892020000400306&tlng=en |
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| author | Rubem Santa Brígida Barros Neto Claudio Nery Lamarão Gisele Tavares Marques Cristina Valle Pinto-Coelho |
| author_facet | Rubem Santa Brígida Barros Neto Claudio Nery Lamarão Gisele Tavares Marques Cristina Valle Pinto-Coelho |
| author_sort | Rubem Santa Brígida Barros Neto |
| collection | DOAJ |
| description | Abstract Quartz and cassiterite crystals of granite, greisens, and quartz veins from Mocambo Granite, Carajás Province, were studied by scanning electron microscopy — cathodoluminescence and electron microprobe. Five types of quartz were identified: Qz1, magmatic and Qz2, Qz3, Qz4, and Qz5 hydrothermal. Qz1, anhedric to subhedric, luminescent and fractured at different intensities, predominating in less evolved rocks. Qz2, with low luminescence, is younger than Qz1; it occurs as irregular patches, filling fractures or forming veins that cut Qz1. Qz3, non-luminescent, resulting from continuous alteration, dissolution, and recrystallization processes; fills fractures that cut Qz1 and Qz2. Qz4 occurs in the most evolved and hydrothermalized rocks and in greisens bodies mineralized in cassiterite; is euhedral to subhedral, exhibits well-defined zoning, and has been interpreted as later than the previous one. Qz5 has poor luminescence; occurs in mineralized veins with wolframite and, secondarily, cassiterite. Qz1 shows Ti enrichment, while Qz4 associated with cassiterite is enriched with Al. Well-formed cassiterite crystals exhibit concentric zoning and low Fe, Ti, W, Nb and Mn contents. Qz5-associated cassiterite crystals form inclusions in the wolframite, suggesting that cassiterite and wolframite precipitated from hydrothermal processes at different times. |
| first_indexed | 2024-12-20T09:35:44Z |
| format | Article |
| id | doaj.art-f4ea6118958e40a8b98ce1c40fddcd2a |
| institution | Directory Open Access Journal |
| issn | 2317-4692 |
| language | English |
| last_indexed | 2024-12-20T09:35:44Z |
| publishDate | 2020-11-01 |
| publisher | Sociedade Brasileira de Geologia |
| record_format | Article |
| series | Brazilian Journal of Geology |
| spelling | doaj.art-f4ea6118958e40a8b98ce1c40fddcd2a2022-12-21T19:45:00ZengSociedade Brasileira de GeologiaBrazilian Journal of Geology2317-46922020-11-0150410.1590/2317-4889202020190096Morphological and compositional study of quartz and cassiterite of the Mocambo Granite, South Pará Tin Province, Amazonian CratonRubem Santa Brígida Barros Netohttps://orcid.org/0000-0001-7398-3202Claudio Nery Lamarãohttps://orcid.org/0000-0002-0672-3977Gisele Tavares Marqueshttps://orcid.org/0000-0003-3122-259XCristina Valle Pinto-Coelhohttps://orcid.org/0000-0003-1470-1337Abstract Quartz and cassiterite crystals of granite, greisens, and quartz veins from Mocambo Granite, Carajás Province, were studied by scanning electron microscopy — cathodoluminescence and electron microprobe. Five types of quartz were identified: Qz1, magmatic and Qz2, Qz3, Qz4, and Qz5 hydrothermal. Qz1, anhedric to subhedric, luminescent and fractured at different intensities, predominating in less evolved rocks. Qz2, with low luminescence, is younger than Qz1; it occurs as irregular patches, filling fractures or forming veins that cut Qz1. Qz3, non-luminescent, resulting from continuous alteration, dissolution, and recrystallization processes; fills fractures that cut Qz1 and Qz2. Qz4 occurs in the most evolved and hydrothermalized rocks and in greisens bodies mineralized in cassiterite; is euhedral to subhedral, exhibits well-defined zoning, and has been interpreted as later than the previous one. Qz5 has poor luminescence; occurs in mineralized veins with wolframite and, secondarily, cassiterite. Qz1 shows Ti enrichment, while Qz4 associated with cassiterite is enriched with Al. Well-formed cassiterite crystals exhibit concentric zoning and low Fe, Ti, W, Nb and Mn contents. Qz5-associated cassiterite crystals form inclusions in the wolframite, suggesting that cassiterite and wolframite precipitated from hydrothermal processes at different times.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892020000400306&tlng=enAmazonian cratonSEM-CL images quartz textureshydrothermal alterationTin mineralizationcassiterite |
| spellingShingle | Rubem Santa Brígida Barros Neto Claudio Nery Lamarão Gisele Tavares Marques Cristina Valle Pinto-Coelho Morphological and compositional study of quartz and cassiterite of the Mocambo Granite, South Pará Tin Province, Amazonian Craton Brazilian Journal of Geology Amazonian craton SEM-CL images quartz textures hydrothermal alteration Tin mineralization cassiterite |
| title | Morphological and compositional study of quartz and cassiterite of the Mocambo Granite, South Pará Tin Province, Amazonian Craton |
| title_full | Morphological and compositional study of quartz and cassiterite of the Mocambo Granite, South Pará Tin Province, Amazonian Craton |
| title_fullStr | Morphological and compositional study of quartz and cassiterite of the Mocambo Granite, South Pará Tin Province, Amazonian Craton |
| title_full_unstemmed | Morphological and compositional study of quartz and cassiterite of the Mocambo Granite, South Pará Tin Province, Amazonian Craton |
| title_short | Morphological and compositional study of quartz and cassiterite of the Mocambo Granite, South Pará Tin Province, Amazonian Craton |
| title_sort | morphological and compositional study of quartz and cassiterite of the mocambo granite south para tin province amazonian craton |
| topic | Amazonian craton SEM-CL images quartz textures hydrothermal alteration Tin mineralization cassiterite |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892020000400306&tlng=en |
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